I did it once for my sister using a TP-Link router. it er, well, works, but it did work after configuring and reconfiguring the router several times, turned out the modem kept reverting to the wrong settings, and consequently wouldn't get detected It seems these new PowerTel modems (January 2013 and later) have issues with a good number of routers, they constantly revert to the ChinaMobile configuration, for no apparent reason. (in this case, i changed the ChinaMobile configuration to Powertel values, so that each time it reverted to these settings, it would keep working, and voila! it did work.
i suggest you take a look at the log file, it might give you some answers